The following patch attempts to implement LWG4483. As written in the
approved resolution, some checks are done on strip_array_types (valuet)
rather than on valuet and one is skipped. Tomasz on IRC reasoned why
input_range should otherwise already ensure we see similar type, so just
for the possibility of fuzzed <meta> the patch adds some verification.
And as the array cases are contiguous, instead of actually recursing (for
which we'd need to have lvalue of the *it rather than prvalue) it just
walks the CONSTRUCTORs for the arrays and handles the elts in there
recursively.
The <meta> changes do exactly what the LWG4483 change says to do.
2026-04-15 Jakub Jelinek <jakub@redhat.com>
* reflect.cc (adjust_array_elt): New function.
(get_range_elts): Implement LWG4483 - Multidimensional arrays are not
supported by meta::reflect_constant_array and related functions.
Handle ARRAY_TYPE valuet. Don't unshare_expr in the class valuet case,
get_template_param_object will unshare.
* g++.dg/reflect/reflect_constant_array9.C: New test.
* g++.dg/reflect/reflect_constant_array10.C: New test.
* g++.dg/reflect/reflect_constant_array11.C: New test.
* g++.dg/reflect/define_static_array6.C: New test.
* g++.dg/reflect/define_static_object2.C: Uncomment older tests and
fix them, add tests for unions.
* include/std/meta (define_static_object): Adjust for LWG4483 changes
- handle unions and arrays differently.
Reviewed-by: Jason Merrill <jason@redhat.com>
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
2cdd7831e3